1. Field of the Invention
The present invention relates to a method of fabricating a liquid film, a method of arranging nano particles and a substrate having a liquid thin film fabricated using the same, and more particularly to a method of fabricating a liquid film having a constant size in nano size, a method of arranging nano particles and a substrate having a liquid thin film fabricated using the same.
2. Description of the Prior Art
An electro wetting means a phenomenon that electric charges existing on an interface are controlled to thereby change surface tension at the interface. Using such electro wetting, micro liquid and micro particles in liquid can be controlled so that researches are recently conducted to diverse products using electro wetting.
As a field to which electro wetting is applicable, there are a liquid lens, a display device, a memory, a switch, an optical device, a liquid magnet, and an MEMS. Particularly, the display device using electro wetting has an advantage in that power consumption is lower than existing liquid crystal display. Further, an auto-focus liquid lens using electro wetting has many advantages of miniaturization, rapid response speed, and low power consumption as compared to a driving mode of existing lens.
A method of controlling liquid and micro particles in liquid using electro wetting is used in forming a liquid film on a substrate and arranging the micro particles thereon. For example, the liquid film is formed in a display device, so that color elements of Red, Green, Blue, etc. can be selectively and densely arranged on a display unit of the substrate.
The formation of the liquid film on the substrate is not easy due to surface tension acting at an interface between the substrate and the liquid applied to the substrate. Thus, if different voltages are respectively applied to the substrate and the liquid applied to the substrate using the electro wetting principle, the surface tension between the substrate and the liquid is reduced so that the substrate can be wetted with the liquid.
However, in case where nano size liquid film is formed on the substrate, since the amount of the liquid applied to the substrate is quite a small, it has a limit to reduce the surface tension with only application of voltage. Thus, it is very difficult for the nano size liquid film to constantly wet the whole surface of the substrate, and the liquid film formed on the substrate is ready to be exposed to air and thus be evaporated, so that the thickness of the liquid film cannot be kept constant.